JP6971634B2 - Constant velocity universal joint - Google Patents

Description

The present invention relates to a constant velocity universal joint, and particularly to a triball joint.

As a constant velocity universal joint, there is a joint called a "triball joint" as shown in Patent Document 1 and Patent Document 2. As shown in FIGS. 6 to 8, the tri-ball joint has an outer ring 2 integrated with the central shaft portion 1 and a torque tube 4 having three ball holes (pockets) formed in the three balls. The transmission power is transmitted through 5.

That is, the outer ring 2 includes an outer peripheral wall 2a, a bottom wall 2b, and the central shaft portion 1 projecting from the bottom wall 2b, whereby an annular space 6 having one end opened is formed. Three track grooves 7 and 8 extending in the axial direction are formed on the outer wall surface 9a and the inner wall surface 9b of the annular space 6 at an interval of 120 ° in the circumferential direction. The bottom wall 2b is provided with a short tubular boss portion 10 having a hole portion 10a formed therein.

Further, the central shaft portion 1 has a small diameter shaft portion 1a on the back side of the joint, that is, on the bottom wall 2b side, a large diameter portion 1b connected to the tip of the small diameter shaft portion 1a, and a tip surface of the large diameter portion 1b. It is composed of a bulging portion 1c projecting from. Then, three track grooves 8 extending in the axial direction from a part of the small diameter shaft portion 1a to the large diameter portion 1b are formed at a pitch of 120 ° along the circumferential direction. The end face of the bulging portion 1c is a convex curved surface 11.

The torque tube 4 has a ring portion 13 having three pockets 3 at a pitch of 120 ° along the circumferential direction, and the outer diameter of the torque tube 4 is reduced toward the back side of the joint from the ring portion 13 on the back side of the joint. A first tapered portion 14, a second tapered portion 15 whose outer diameter is reduced toward the joint opening side from the annular portion 13 on the joint opening side, and a connecting shaft portion extending from the second tapered portion 15 to the joint opening side. 16 and a boss portion 17 connected to the anti-annular portion side from the connecting shaft portion 16 are provided. An edge tapered portion 22 whose diameter increases toward the inner side of the joint is formed on the edge of the inner diameter surface of the torque tube 4 (the inner diameter surface of the hole 20 into which the central shaft portion 1 is fitted). The boss portion 17 is provided with a through hole 17a.

The hole 20 of the torque tube 4 includes a bottom surface 20a, a concave spherical surface 20b rising from the bottom surface 20a, and a main body cylindrical surface portion 20c, and the edge tapered portion 22 is formed at the opening edge portion of the main body cylindrical surface portion 20c. .. The radius of curvature K1 of the concave spherical surface 20b of the hole 20 of the torque tube 4 is set to be larger than the radius of curvature of the convex curved surface 11 of the bulging portion 1c.

Further, a stop ring 30 is arranged on the inner diameter surface of the outer peripheral wall on the opening side of the outer ring 2 to prevent the ball from coming off, and the opening of the outer ring 2 is sealed by the boot 31. That is, the boot 31 includes a large diameter portion 31a, a small diameter portion 31b, and a bellows portion 31c that connects the large diameter portion 31a and the small diameter portion 31b. Then, the large diameter portion 31a is externally fitted to the open end of the outer ring 2 and tightened with the boot band 32, and the small diameter portion 31b is externally fitted to a predetermined position of the torque tube 4 and tightened with the boot band 32. The stop ring 30 is fitted in a circumferential groove 29 provided on the inner diameter surface of the outer peripheral wall on the opening side of the outer ring 2. Further, the convex ridge portion 31a1 formed on the inner diameter surface of the large diameter portion 31a of the boot 31 is fitted into the circumferential concave groove 33 provided on the opening side of the outer diameter surface of the outer peripheral wall 2a of the outer ring 2, and the boss is formed. A convex ridge 31b1 formed on the inner diameter surface of the small diameter portion 31b of the boot 31 is fitted into the circumferential concave groove 34 provided on the outer diameter surface of the portion 17.

By the way, when the working angle is taken from the state shown in FIG. 8A, the torque tube 4 is eccentric. That is, as shown in FIG. 8B, when the torque tube 4 is tilted toward a portion having no track groove 7 (between the track grooves 7 and 7 adjacent to each other in the circumferential direction), the axis of the torque tube 4 is the arrow X1. Eccentric to the side (track groove side 180 ° opposite to the track grooves 7 and 7). This amount of eccentricity can be expressed by the following equation 1. In FIG. 8, the description of the boot 31 and the boot band 32 is omitted.

Further, as shown in FIG. 8C, when the torque tube 4 is tilted toward one track 7, the axis of the torque tube 4 has a track groove 7 on the arrow X2 side (180 ° opposite to the track groove). Eccentric to the part that does not). The amount of eccentricity in this case can also be expressed by the above-mentioned number 1.

Japanese Unexamined Patent Publication No. 2013-44349 Japanese Unexamined Patent Publication No. 2014-25486

The tri-ball joint has a mechanism that is eccentric and maintains constant velocity by imparting an operating angle. However, the maximum allowable angle is limited by the shapes of the outer ring 2 and the torque tube 4, it is difficult to increase the angle, and the allowable operating angle is 20 deg as a standard. As shown in FIGS. 8 (b) and 8 (c), the allowable operating angle is the contact between the tapered surfaces 14 and 15 of the torque tube 4 with the outer wall surface 9a of the annular space 6 of the outer ring 2 and the tapered surface 22 of the torque tube 4. It is determined by the contact of the outer ring 2 with the small diameter shaft portion 1a, the contact of the opening end portion of the hole portion 20 of the torque tube 4 with the central shaft portion 1, and the like. Therefore, it is necessary to avoid interference between the central shaft portion 1 of the outer ring 2 and the inner diameter surface of the torque tube 4, and in consideration of the strength, the design is limited to an allowable operating angle of 20 deg. On the other hand, even if the strength is reduced, there are many demands for increasing the angle of the constant velocity universal joint.

Therefore, in view of the above problems, the present invention provides a high-angle tri-ball joint that can secure the required strength while maintaining compactness and can have an allowable operating angle larger than 20 deg.

The constant velocity universal joint of the present invention forms an annular space in which one end opens by projecting a central shaft portion from the bottom wall, and three tracks extending axially on each of the outer wall surface and the inner wall surface of the annular space. An outer ring having grooves formed at intervals of 120 ° in the circumferential direction, and a torque tube having an end incorporated in the annular space of the outer ring and pockets formed at positions corresponding to each of the track grooves. , A uniform speed universal joint equipped with a ball that is built into the pocket of the torque tube and can roll along the track groove, and when the working angle is taken, the central shaft portion and the torque tube are provided. It is provided with a range-increasing structure for increasing the range until contact with the outer ring to increase the allowable operating angle, and this range-increasing structure is provided between the outer ring and the torque tube, and the central shaft portion is provided. A small-diameter shaft on the back side of the joint, a tapered part on the back side that is connected to the opening side of the joint of this small-diameter shaft and expands toward the opening side of the joint, and a tapered part on the back side that is connected to the opening side of the joint. It has a large-diameter shaft portion and an opening-side tapered portion that is connected to the joint opening side of the large-diameter shaft portion and reduces the diameter toward the joint opening side. The range-increasing structure is formed by the above, and the tip portion of the central shaft portion on the joint opening side is a convex curved surface, and the torque tube is provided with a hole into which the central shaft portion is fitted, and the hole is formed. parts includes a bottom surface, a concave spherical surface which rises from the bottom surface, and a body cylindrical surface, convex surface of the central shaft portion is capable opposed to the bottom surface of the hole, the concave spherical surface of the hole portion of the torque tube The radius of curvature of is set to be larger than the radius of curvature of the convex curved surface of the central axis portion. Here, increasing the interference range means increasing the range until the central shaft portion and the torque tube come into contact with each other when the working angle is taken, in order to increase the allowable working angle.

According to the constant velocity universal joint of the present invention, the allowable operating angle can be increased by providing the range-increasing structure. Moreover, the central shaft portion of the outer ring can have a portion other than the range-increasing structure at least the same as the central shaft portion of the conventional triball joint of this type, and is stable in terms of strength.

The central shaft portion includes a small-diameter shaft portion on the back side of the joint, a back-side tapered portion that is connected to the joint opening side of the small-diameter shaft portion and expands in diameter toward the joint opening side, and a joint of the back-side tapered portion. It has a large-diameter shaft portion connected to the opening side and an opening-side tapered portion connected to the joint opening side of the large-diameter shaft portion to reduce the diameter toward the joint opening side, and the opening-side tapered portion. And the inner taper portion can form the range-increasing structure. Therefore, the structure is such that the taper portion on the back side and the taper portion on the opening side increase the contact margin between the central shaft portion and the torque tube.

The torque tube has an annular portion in which the pocket is formed, a first tapered portion whose outer diameter is reduced toward the interior of the joint on the inner side of the joint from the annular portion, and a joint opening side of the annular portion. A second tapered portion whose outer diameter decreases toward the joint opening side, a connecting shaft portion protruding from the second tapered portion toward the joint opening side, and a boss connected from this connecting shaft portion to the anti-annular portion side. The connecting shaft portion is provided with a portion, and the connecting shaft portion is used as a connecting shaft side slime portion for avoiding contact with the opening end portion of the outer ring, and the small diameter shaft portion of the central shaft portion is used as the opening end portion of the torque tube. The small diameter shaft side stiff part that avoids contact is used, and the outer diameter dimension of each stiff part is 1 / 1.5 times the outer diameter dimension of each stiff part of the joint having an allowable operating angle of 20 deg, and the outer ring. It is preferable that the axial length of the track groove of the joint is 1.2 to 1.3 times the axial length of the track groove of the outer ring of the joint having an allowable operating angle of 20 deg.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a constant velocity universal joint of a tri-ball joint which can secure the required strength while maintaining compactness and can have a large allowable operating angle.

It is sectional drawing of the constant velocity universal joint (triball joint) of this invention. It is an enlarged view of the main part of the tri-ball joint of FIG. The outer ring of the tri-ball joint of FIG. 1 is shown, (a) is a sectional view, and (b) is a front view. It is sectional drawing of the torque tube of the tri-ball joint of FIG. The tri-ball joint of FIG. 1 is shown, (a) is a cross-sectional view in a state where the working angle is not taken, (b) is a cross-sectional view in a state where an allowable working angle is taken, and (c) is (b). It is sectional drawing of the state which took the permissible operating angle in the direction different from. It is sectional drawing of the conventional tri-ball joint. It is a perspective view which shows the partial cross section of the conventional tri-ball joint. A conventional tri-ball joint is shown, (a) is a cross-sectional view in a state where the working angle is not taken, (b) is a cross-sectional view in a state where an allowable working angle is taken, and (c) is (b). It is sectional drawing in the state which took the permissible operating angle in a different direction.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 shows a constant velocity universal joint (triball joint) according to the present invention. In this constant velocity universal joint, an outer ring 52 integrated with a central shaft portion 51 and a torque tube 54 in which three ball holes (pockets) 53 are formed transmit a transmission force via three balls 55. It has become like.

That is, as shown in FIGS. 3A and 3B, the outer ring 52 includes an outer peripheral wall 52a, a bottom wall 52b, and the central shaft portion 51 projecting from the bottom wall 52b, whereby one end thereof is provided. An annular space 56 is formed. Three track grooves 57, 58 extending in the axial direction are formed on the outer wall surface 59a and the inner wall surface 59b of the annular space 56 at intervals of 120 ° in the circumferential direction. The bottom wall 52b is provided with a short tubular boss portion 60 having a hole portion 60a formed therein.

Further, the central shaft portion 51 includes a small diameter shaft portion 51a on the back side of the joint, that is, the bottom wall 52b side, a back side tapered portion 51b connected to the joint opening side of the small diameter shaft portion 51a, and the back side tapered portion. It has a large-diameter shaft portion 51c connected to the joint opening side of the 51b, and an opening-side tapered portion 51d connected to the joint opening side of the large-diameter shaft portion 51c. The inner taper portion 51b is a tapered portion whose diameter increases from the small diameter shaft portion 51a side toward the joint opening side, and the opening side tapered portion 51d reduces the diameter from the large diameter shaft portion 51c side toward the joint opening side. It is a tapered part. Then, three track grooves 58 extending in the axial direction from the inner tapered portion 51b to the opening side tapered portion 51d are formed at a pitch of 120 ° along the circumferential direction.

As shown in FIG. 4, the torque tube 54 has an annular portion 63 having three pockets 53 at a pitch of 120 ° along the circumferential direction, and the outer diameter of the torque tube 54 is closer to the inner side of the joint than the annular portion 63. A first tapered portion 64 whose diameter is reduced toward the side, a second tapered portion 65 whose outer diameter is reduced toward the joint opening side on the joint opening side of the annular portion 63, and a joint from the second tapered portion 65. A connecting shaft portion 66 projecting from the opening side and a boss portion 67 connected to the anti-annular portion side from the connecting shaft portion 66 are provided. The boss portion 67 is provided with a through hole 67a. The torque tube 54 is formed with a hole 70 into which the central shaft portion 51 of the outer ring 52 is fitted.

The hole 70 of the torque tube 54 includes a bottom surface 70a, a concave spherical surface 70b rising from the bottom surface 70a, and a main body cylindrical surface portion 70c, and the edge tapered portion 72 is formed at the opening edge portion of the main body cylindrical surface portion 70c. .. Further, as shown in FIG. 3, the tip portion of the central shaft portion 51 is a convex curved surface 51e. The radius of curvature K (see FIG. 2) of the concave spherical surface 70b of the hole 70 of the torque tube 54 is set to be larger than the radius of curvature of the convex curved surface 51e.

In this case, the small diameter shaft portion 51a is a hole portion of the torque tube 54 into which the central shaft portion 51 is fitted when the constant velocity universal joint takes an operating angle, as shown in FIGS. 5 (b) and 5 (c). It constitutes a small diameter shaft side slime portion that does not contact the open end portion of 70. Further, the edge tapered portion 72 is formed on the edge of the inner diameter surface (inner diameter surface of the hole 70) of the torque tube 54 so as to expand in diameter toward the inner side of the joint.

As shown in FIGS. 1 and 2, a stop ring 80 for preventing the ball from coming off is disposed on the inner diameter surface of the outer peripheral wall on the opening side of the outer ring 52, and the opening of the outer ring 52 is sealed by the boot 81. That is, the boot 81 includes a large diameter portion 81a, a small diameter portion 81b, and a bellows portion 81c connecting the large diameter portion 81a and the small diameter portion 81b. Then, the large diameter portion 81a is externally fitted to the open end of the outer ring 52 and tightened with the boot band 82, and the small diameter portion 81b is externally fitted to a predetermined position of the torque tube 54 and tightened with the boot band 82. The stop ring 80 is fitted in a circumferential groove 79 provided on the inner diameter surface of the outer peripheral wall on the opening side of the outer ring 52. Further, the convex ridge 81a1 formed on the inner diameter surface of the large diameter portion 81a of the boot 81 is fitted into the circumferential concave groove 83 provided on the outer diameter surface on the opening side of the outer peripheral wall 52a of the outer ring 52, and the torque is increased. A convex ridge 81b1 formed on the inner diameter surface of the small diameter portion 81b of the boot 81 is fitted in a circumferential concave groove 84 provided on the outer diameter surface of the boss portion 67 of the tube 54.

By the way, when the constant velocity universal joint configured as described above takes the working angle shown in FIGS. 5 (b) and 5 (c) from the state where the working angle shown in FIG. 5 (a) is not taken, the torque tube 54 Will be eccentric. That is, as shown in FIG. 5B, when the torque tube 54 is inclined toward a portion having no track grooves 57, 58 (between the track grooves 57 and 57 adjacent to each other in the circumferential direction), the axial center of the torque tube 54 becomes. It is eccentric to the arrow X1 side (track groove 57 side in the direction 180 ° opposite to the track groove 57, 57). This amount of eccentricity can be expressed by the above-mentioned number 1. In FIG. 5, the description of the boot 81 and the boot band 82 is omitted.

Further, as shown in FIG. 5C, when the torque tube 54 is tilted toward one track 57, the axis of the torque tube 54 has a track groove 57 on the arrow X2 side (180 ° opposite to the track groove). Eccentric to the part that does not). The amount of eccentricity in this case can also be expressed by the above-mentioned number 1.

As described above, the constant velocity universal joint configured as described above has an allowable operating angle of 30 deg. Therefore, it is compared with the triball joint shown in FIG. 6, which has an allowable operating angle of 20 deg. In the outer ring 2 of FIG. 6, the effective length of the track groove 7 of the outer ring 2 is A1, the outer diameter of the base portion of the central shaft portion 1 is B1, and in the constant velocity universal joint shown in FIG. 2, the track of the outer ring 52. When the effective length of the groove 57 is A and the outer diameter of the base portion of the central shaft portion 51, that is, the small diameter shaft portion 51a is B, A is about 1.2 times to about 1.3 times that of A1. B is about 1 / 1.5 times that of B1.

Further, in the torque tube 4 of FIG. 6, when the outer diameter dimension of the connecting shaft portion 16 is D1, and in the torque tube 54 of FIG. 2, the outer diameter dimension of the connecting shaft portion 66 is D, D is 1 of D1. /1.5 times. In the torque tube 4 of FIG. 6, when the inclination angle of the tapered portion 14 is E1, the inclination angle of the edge tapered portion 22 is F1, and the inclination angle of the tapered portion 15 is G1, each E, F, G is 20 deg. It is supposed to be. On the other hand, in the torque tube 54 of FIG. 2, when the inclination angle of the tapered portion 64 is E, the inclination angle of the edge tapered portion 72 is F, and the inclination angle of the tapered portion 65 is G, E. F and G are set to 30 deg, which is larger than E1, F1 and G1.

The amount of deviation from the joint center of the curvature center of the convex curved surface 11 of the bulging portion 1c of the central shaft portion 1 of FIG. 6 is L1, and the tip portion of the central shaft portion 51 of FIG. 2 is the joint center of the curvature center of the convex curved surface 51e. When the amount of deviation from is L, L is made larger than L1, for example, about twice.

By the way, in the central shaft portion 51 of the outer ring 52 of the constant velocity universal joint according to the present invention, as shown in FIG. The opening side tapered portion 51d is provided. In this case, when the inclination angle of the back side tapered portion 51b is H and the inclination angle of the opening side tapered portion 51d is J, H and J are set to about 30 deg.

Therefore, when the operating angle is taken as shown in FIGS. 5 (b) and 5 (c) from the state shown in FIG. 5 (a), the allowable operating angle is 30 deg. That is, by reducing the outer diameter dimension of the small diameter shaft portion 51a which is the base of the central shaft portion 51, it is possible to avoid contact with the open end portion of the torque tube 54, and the small diameter shaft side stiff portion N2 is configured. Can be done. Further, by reducing the outer diameter dimension of the connecting shaft portion 66 of the torque tube 54, it is possible to configure the connecting shaft side stiff portion N1 for avoiding contact with the open end portion of the outer ring.

Further, since the central shaft portion 51 is provided with the inner tapered portion 51b and the opening side tapered portion 51d having an inclination angle of 30 deg, the range increasing structure M for increasing the interference range between the central shaft portion 51 and the torque tube 54 is provided. , M will be provided between the outer ring 52 and the torque tube 54. That is, the range-increasing structures M and M are composed of the back side tapered portion 51b and the opening side tapered portion 51d. Therefore, as shown in FIGS. 5B and 5C, the working angle is taken until the inner tapered portion 51b and the opening tapered portion 51d are parallel to the outer wall surface 59a of the annular space 56 of the outer ring 52. And this is 30 deg. In this way, increasing the interference range means increasing the range until the central shaft portion 51 and the torque tube 54 come into contact with each other when the working angle is taken, in order to increase the allowable working angle. be.

In the present invention, the allowable operating angle can be increased by providing the range increasing structure M. Moreover, the central shaft portion 51 can have a portion other than the range-increasing structure M at least the same as the central shaft portion of the conventional triball joint of this type, and is stable in terms of strength. Therefore, it is possible to provide a constant velocity universal joint of a tri-ball joint which can have a large allowable operating angle and is stable in terms of strength.

By setting the dimensions A, B, D, L, and the angles E, F, G, H, and J as described above, the contact between the outer ring 52 and the torque tube 54 is maintained until an allowable operating angle of 30 deg is obtained. It can be stably avoided, and the strength of the outer ring 52 and the torque tube 54 can also be stabilized.

By the way, the eccentricity amount γ (see FIGS. 5 and 8) in the state where the working angle is given becomes larger as the ball PCR and the working angle become larger in calculation. Therefore, if an attempt is made to design a product having an allowable operating angle of 30 deg as shown in FIG. 5, the eccentricity amount γ becomes large. Therefore, considering the contact (interference) between the outer ring 52 and the torque tube 54 at the allowable operating angle, the eccentricity amount is the dimensions A, B, D, L, and the angles E, F, G, H, J. Will be set. Further, if it is attempted to design a product having the same strength as the conventional product shown in FIG. 6 and having an allowable operating angle of 30 deg, the outer diameter of the outer ring will be about 1.5 times that of the conventional product.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be variously modified. In the embodiment, the so-called constant velocity universal joint does not have a flange portion. Although it was a boss type, it may be a so-called flange type having a flange portion or a semi-finished flange type. When changing the allowable operating angle, the dimensions A, B, D, L, the angles E, F, G, H, J, etc. may be changed according to the operating angle.

51 Central shaft part 51a Small diameter shaft part 51b Back taper part 51c Large diameter shaft part 51d Open side taper part 52 Outer ring 52b Bottom wall 53 Pocket 54 Torque tube 55 Ball 56 Circular space 57, 58 Track groove 59a Outer wall surface 59b Inner wall surface 63 Ring part 64 1st taper part 65 2nd taper part 66 Connecting shaft part 67 Boss part 72 Edge taper part N1 Connecting shaft side sewn part N2 Small diameter shaft side sewn part M Range increase structure

Claims (2)

An annular space is formed in which one end is opened by projecting the central shaft portion from the bottom wall, and three track grooves extending in the axial direction are spaced 120 ° in the circumferential direction on each of the outer wall surface and the inner wall surface of the annular space. A torque tube having an outer ring formed at the same time and an end portion incorporated in the annular space of the outer ring and pockets formed at positions corresponding to each of the track grooves, and a torque tube incorporated into the pocket of the torque tube. It is a constant velocity universal joint equipped with a ball that can roll along the track groove.
When the working angle is taken, the range until the central shaft portion and the torque tube come into contact is increased to provide a range increasing structure for increasing the allowable working angle, and this range increasing structure includes the outer ring and torque. It is provided between the tube and
The central shaft portion includes a small-diameter shaft portion on the back side of the joint, a back-side tapered portion that is connected to the joint opening side of the small-diameter shaft portion and expands in diameter toward the joint opening side, and a joint of the back-side tapered portion. It has a large-diameter shaft portion connected to the opening side and an opening-side tapered portion connected to the joint opening side of the large-diameter shaft portion to reduce the diameter toward the joint opening side, and the opening-side tapered portion. And the inner taper portion form the range-increasing structure.
The tip of the central shaft portion on the joint opening side has a convex curved surface, and the torque tube has a hole into which the central shaft is fitted, and the hole rises from the bottom surface and the bottom surface. and the concave spherical surface, and a body cylindrical surface, the convex surface of the center shaft portion is capable opposed to the bottom surface of the hole, the convex radius of curvature of the concave spherical surface of the hole portion of the torque tube of the central shaft portion A constant velocity universal joint characterized by being set larger than the radius of curvature of a curved surface. The torque tube has an annular portion in which the pocket is formed, a first tapered portion whose outer diameter is reduced toward the inner side of the joint on the inner side of the joint from the annular portion, and a joint opening rather than the annular portion. A second tapered portion whose outer diameter decreases toward the joint opening side, a connecting shaft portion extending from the second tapered portion to the joint opening side, and a boss connected from this connecting shaft portion to the anti-annular ring portion side. The connecting shaft portion is provided with a portion, and the connecting shaft portion is used as a slime portion for avoiding contact with the open end portion of the outer ring, and the small diameter shaft portion of the central shaft portion avoids contact with the open end portion of the torque tube. The outer diameter of each slip is set to 1 / 1.5 times the outer diameter of each of the joints having an allowable operating angle of 20 deg, and the axial length of the track groove of the outer ring is set. The constant velocity universal joint according to claim 1, wherein the allowable operating angle is 1.2 to 1.3 times the axial length of the track groove of the outer ring of the joint.

Images